Extrusion presses

ABSTRACT

AN EXTRUSION PRESS HAVING TWO OR MORE MAIN CYLINDERS IN WHICH THE FREE SPACE BETWEEN THE CYLINDERS IS USED TO ACCOMMODATE GUIDE MEANS FOR THE MOVING CROSSHEAD. INDIVIDUAL SUPPORTING MEANS ARE PROVIDED FOR EACH CYLINDER THROUGH WHICH THE WEIGHT OF HAT CYLINDER IS INDEPENDENTLY TRANSMITTED TO THE PRESS-BED.

NOV, 16, 1971 RJ, ELGER ETAL 3,620,064

EXTRUSION PRESSES Filed July E, 1969 5 Shoots-Shoot 1 V 1h u m w: E Q"e* Hi C) "r N --g/ N l 'Ol j sa y l @s mag lL Nov. 16,1971 RJ. ELGERErAL 3,620,064

' EXTRUSION PRESSES Filed July 2, 1969 5 Sheets-Sheet 2 Nov. 16, 1971 R,J, ELC-3ER ETAL 3,620,064

EXTRUSION PRESSES Filed July s, 1969 I 5 sheets-sheet EXTRUSION PRESSES5 Sheets-Shea?I 4 Filed July 2, 1969 Umm. N

Nov. 16, 1971 R 1 ELGER EIAL 3,620,064

ExTRUsIoN PRESSES Filed July a, 1969 5 sheets-sheet s United StatesPatent O U.S. Cl. 72-272 18 Claims ABSTRACT F THE DISCLOSURE Anextrusion press having two or more main cylinders in which the -freespace between the cylinders is used to accommodate guide means for themoving crosshead. Individual supporting means are provided for eachcylinder through which the weight of that cylinder is independentlytransmitted to the press-bed.

This invention relates to extrusion presses.

According to the present invention there is provided an extrusion presshaving two or more substantially parallel main cylinders groupedsymmetrically to dene a free space therebetween, the cylinders beingarranged, in use, to drive the moving crosshead of the press, the saidcrosshead carrying an extension disposed in the said free space, theextension being engageable with guide means to ensure true longitudinalmovement of the said crosshead relative to the press axis, and theweight of the cylinders being transmitted to the press-bed without theuse of conventional cylinder crossheads. The guide means may be arrangedso that .guiding of the moving crosshead is effected independently ofmisalignment of, and/or small differences in force exerted by the maincylinders. In this case, the guide means may comprise one or morelongitudinally extending slideways secured to the press-bed.Alternatively, the guide means may comprise one or more longitudinallyextending slideways secured on the facing sides of the two or more maincylinders. In both cases the extension may be provided with one or moreguide surfaces for engaging the or a corresponding slideway.

The moving crosshead itself may be provided with guide surfacesengageable with corresponding longitudinally extending Aguide memberssecured to the pressbed. A pair of guide members may be provided whichare arranged on opposite sides of the press-bed.

Advantageously, the moving crosshead and the main cylinder rams areconnected, the connection being designed with suicient free movement toensure that guiding of the moving crosshead is effected independently ofmisalignment of, and/or small differences in force exerted by the maincylinders.

The extension may be constituted by a stalk-like member which can beeither integral with or secured to the mowing crosshead.

When the press is used for tube extruding the stalklike member may beconstructed to permit throughpassage of a mandrel holder. Further, oneor both ends of the stalk-member may be provided with means for limitingthe stroke ofthe press mandrel relative to the press stem. The limitmeans may comprise a longitudinally adjustable, non-rotatable bushsurrounding the mandrel holder, said'bush being engageable with a stopmember secured to the mandrel holder. The bush may be eX- ternallyscrew-threaded and held in the stalk-member by a captive nut, the nutbeing disposed in the stalk-member so that rotation thereof providesaxial adjustment of the bush.

3,620,064 Patented Nov. 16, 1971 Furthermore, means may be provided forlocking the mandrel holder against relative axial movement with respectto the die. The locking means may be constituted by a transverselymovable locking member mounted on a main cylinder and by a stop memberprovided on the mandrel holder, the axial position of the stop-member onthe holder being arranged so that when, in use, the mandrel is in itsextruding position, the locking member may be moved to engage the stopmember. The stop member may be mounted on the holder so that it can bemoved axially into a number of xed positions thereon. A locking membermay be provided on each of the main cylinders.

The invention will now be described with reference to the accompanyingdrawings, of which:

FIG. 1 is a schematic side elevation, partly in section, of a irstembodiment of the invention;

FIG. 2 is a plan view, partly in section, of the embodiment of FIG. l;

FIG. 3 is a section taken at III-III of FIG. l;

FIG. 4 is a section taken at IV-IV on FIG. 1;

FIG. 5 is a section of one half of a second embodiment of the invention,viewed from above;

FIG. 6 is a vertical section through the second embodiment of theinvention, along the line VI-VI of FIG. 5; and

FIG. 7 is a diagrammatic sectional plan view of a press includingmandrel-arrest equipment.

The embodiment illustrated in FIGS. 1 to 4 is a tube extrusion presshaving two main cylinders, and includes piercer gear.

It will be seen from the drawings that the conventional cylindercrosshead has been dispensed with, the pair of main hydraulic cylinders2a and 2b being supported on the press-bed 1. Consequently, there willbe significant savings in weight and cost of the press. The cylinders 2aand 2b are disposed in spaced side-by-side relation and the rams 3a and3b carry a moving cross-head 4 on which is mounted a hollow extrusionstern 5. The moving cross-head 4 is slidably mounted on the bed 1, bymeans of vertical and horizontal guide members 6 and 7 respectively, formovement parallel to the longitudinal axis of the press, correspondingguide surfaces 6a, 7a being secured to the bed of the machine.

The rear face of the moving cross-head 4 carries a central rearwardlyextending hollow stalk 8, the free end of which is formed with adownwardly extending guide member 9 running on a longitudinal guidetrack 10 secured to the bed 1 of the machine midway between the maincylinders 2a and 2b. The presence of this guide member ensures thatslewing of the stem -5 will be prevented in the event that unevenoperation of the main rams occurs for any reason.

Return of the moving cross-head is effected by four return cylinders 11mounted on the main cylinders with their rams 12 secured to thecross-head.

As the illustrated machine is a tube extrusion press, piercer gear isprovided, and is accommodated partly in the space between the two maincylinders.

The piercer cylinder 13:` is mounted at one end on a iixed cross-head 14supported on a supplementary machine bed 15, and connected to thecylinders 2a, 2b by laterally disposed tie rods 16. The other end ofcylinder 13 has an extrusion 17 which engages in a support bracket onthe bed 115. The iixed cross-head 14 also carries vertically alignedsleeves 1-8 which serve as adjustable stroke limits for a pair ofmandrel-arrest rods 19 secured at one end to a piercer cross-head 20which slides on the guide track 10 under the action of piercer ram 13aand at their other end to a support trolley 21. The mandrel holder 22 ofthe machine is mounted on the piercer cross-head 20, and extends throughthe hollow extension 8 and into the rear of cross-head 4 in which it issupported by a bush 23. A mandrel adapter 24 is screwed into the end ofholder 22, and extends through the cross-head 4 to support the mandrelin the extrusion stem 5.

It will be seen from the drawings and the foregoing description that theguiding of the moving cross-head 4 by the surfaces 6a, 7a and 10 isindependent of misalignment of, and/or small differences in forceexerted by the main cylinders 2a and 2b. To maintain this independenceduring operation, the connection between the rams 3a and 3b and themoving cross-head 4 is designed with suflicient free movement toaccommodate the misalignment and/or unequal cylinder forces encounteredin practice. Thus, alignment and adjustment of the moving cross-head issubstantially unatected by such effects as wear of the main ram bushes,which cause variation in the alignment of the main rams.

The second embodiment of the invention, illustrated in FIGS. 5 and 6, isalso a tube extrusion press, but has a guide stem integral with themoving cross-head and shows mandrel stroke limiting arrangements.(Reference numerals, where possible, correspond to those used in FIGS. lto 4.)

The general layout of the press is similar to that of the rstembodiment, and in particular the cylinders are again supported on thepress-bed instead of by a conventional cylinder crosshead. Two mainrams, of which one is shown at 3a, carry a moving cross-head 4 whichsupports an extrusion stem 5. The cross-head moves on a pair of spacedguides (not shown, but similar to 6, 7 in the first embodiment), whilethe third set of guides is provided at the end of an integral rearwardextrusion 8 of the moving cross-head. This extension is of opentrough-like form, and has its free end closed by a vertical wall 26bored at 27 and provided with a bush 28 to serve as a bearing for themandrel holder 22. The forward end of the mandrel holder is carried inbushing 23 in the cross-head 4, and supports a piercer adaptor andmandrel as in the case of the tirst embodiment,

The rear end of the extension 8 is provided with vertical and horizontalguide members 29 and 30 respectively, engaging corresponding guidesurfaces 31, 32 mounted on the facing wall of the two main cylinders 2a,2b, -giving guidance which is independent of the misalignment of, and/orsmall differences in force exerted by the main rams as in the case ofthe first embodiment.

In extrusion of tubes, it is necessary to limit the stroke of themandrel relative to the stem. In this ernbodiment of the invention, thiscan be achieved within the space between the main rams.

At each end of the trough-like cavity within the moving cross-headextension there is a captive nut 33a, 33b retained by a Collar 34a, 34h.Each nut is provided with sprocket teeth 35 for rotation by a chainhaving access through the open trough, and engages with external screwthreading on a corresponding bush 36a, 361) surrounding the piercerholder. Thus, rotation of either nut 33a or 33b causes axial adjustmentof the corresponding bush. Rotation of the bushes is prevented by keysengaging keyways in the extension 8. It will be seen from FIG. 5 thatthe mandrel holder has a central integral collar 3'7 which, by itsabutment with the bushes 36a, 36]), limits the stroke of the piercerassembly relative to the stem. This arrangement obviates the need toprovide space for such limit adjustments at a position axially beyondthe main ram cylinders. Another item of equipment located within theaxial extent of the main cylinder assembly is the worm and pinion drive38 used to rotate the piercer holder. It is of course possible toprovide either forward or rearward stroke limitation alone.

Means have been described above for limiting the stroke ot' the mandrelrelative to the moving cross-head 4 and the stem. FIG. 7 illustratesmechanical means for arresting the mandrel relative to the die, whenextrusion is caried out using a stationary mandrel. Such means areessential when a stepped-mandrel 38 is employed, as shown, since abackward force is exerted by the material being extruded on the annularsurface of the stepped portion of the mandrel. Between thestroke-limiting collar 39 and the piercer cylinder 40 the piercer holder41 is formed with a screw-threaded portion 42. Screwed onto this portionis a stop-nut 43 the axial position of which is set so that when themandrel 38 is in its extruding position it abuts flanges 44 formed on apair of laterally disposed housings 45. Mounted in the housings 45 aretwo hydraulic cylinders 46 which operate a pair of locking members 47 toengage the stop-nut 42, as shown in FIG. 7, when the mandrel is in itsextruding position. Consequently, the backward force exerted on themandrel, which becomes acute towards the end of extrusion when theforward frictional drag of the billet on the mandrel is reduced, will beeffectively resisted by locking the mandrel holder as described.

It will be understood that because the two press constructions describedabove are very similar, parts of one can be readily replaced orinterchanged with parts of the other. Thus, for example, the rear end ofthe extension 8 could be provided with a guide member similar to themember 9 instead of the guide members 29 and 30. Again the extension 8could be replaced by an extension similar in form to 8 in which case themandrel stroke limiting means could also be interchanged` These are onlyexamples of what can be done and other interchanges or replacements willbe readily apparent to one skilled in the art.

It will also be evident that the invention is not limited totube-extruding presses and is equally applicable to rod-extrusion whereno piercer gear will be required. In the case of a tube press, however,an additional advantage is achieved since the free space between themain cylinders can be used for accommodating the piercer gear, thuskeeping the overall length of the press to an absolute minimum.

We claim:

ll. An extrusion press having two or more substantially parallel maincylinders grouped symmetrically to define a free space therebetween, thecylinders being arranged, in use, to drive the moving crosshead of thepress, the said crosshead carrying an extension disposed in the saidfree space, the extension being engageable with guide means to ensuretrue longitudinal movement of the said crosshead relative to the pressaxis, and said press comprising individual supporting means for eachcylinder through which the weight of that cylinder is independentlytransmitted to the press-bed.

2. An extrusion press according to claim 1, in which the guide means arearranged so that guiding of the moving crosshead is effectedindependently of misalignment of, and/or small diiferences in forceexerted by the main cylinders.

3. A press as claimed in claim 1. in which the guide means comprise oneor more longitudinally extending slideways secured to the press-bed.

4. A press as claimed in claim 3, in which the extension is providedwith one or more guide surfaces for engaging the or a correspondingslideway.

5. A press as claimed in claim 1, in which the guide means comprise oneor more longitudinally extending slideways secured on the facing sidesof the two or more main cylinders.

6. A press as claimed in claim 5, in which the extension is providedwith one or more guide surfaces for engaging the or a correspondingslideway.

7. A press as claimed in claim 6, in which a pair of said guide membersare provided and are arranged on opposite sides ofthe press-bed.

8. A press as claimed in claim 1, in which the moving crosshead itselfis provided with guide surfaces engageable with correspondinglongitudinally extending guide members secured to the press-bed.

9. A press as claimed in claim 1, in which the moving crosshead and themain cylinder rams are connected, the connection being designed withsufficient free movement to ensure that guiding of the moving crossheadis effected independently of misalignment of, and/or small differencesin force exerted by, the main cylinders.

10. A press as claimed in claim 1, in which the extension is constitutedby a stalk-like member which can be either integral with or secured tothe moving crosshead.

11. A press as claimed in claim 10, in which the stalklike member isconstructed to permit through-passage of a mandrel holder when the pressis used for tube extruding.

12. A press as claimed in claim 11, in which one or both ends of thestalk member are provided with means for limiting the stroke of thepress mandrel relative to the press stem.

13. A press as claimed in claim 12, in which said limit means comprise alongitudinally adjustable, non-rotatable bush surrounding the mandrelholder, said bush being engageable with a stop member secured to themandrel holder.

14. A press as claimed in claim 13, in which the bush is externallyscrew-threaded and is held in the stalk member by a captive nut, the nutbeing disposed in the stalk member so that rotation thereof providesaxial adjustment of the bush.

15. A press as claimed in claim 11, in which means are provided forlocking the mandrel holder against relative axial movement with respectto the die.

16. A press as claimed in claim 15, in which the locking means areconstituted by a transversely movable locking member mounted on a maincylinder and by a stop member provided on the mandrel holder, the axialposition of the stop member on the holder being arranged so that when,in use, the mandrel is in its extending position, the locking member maybe moved to engage the stop member.

17. A press as claimed in claim 16, in which the stop member is mountedon the holder so that it can be moved axially into a number of fixedpositions thereon.

18. A press as claimed in claim 17, in which a locking member isprovided on each of the main cylinders.

References Cited UNITED STATES PATENTS 638,808 12/1899 Holinger 72-2721,548,457 8/ 1925 Greayer. 2,075,803 4/1937 Dingl et al. 72-2722,778,495 l/1957 Krause 72--272 3,334,507 8/l967 Green et al 72-2723,350,911 ll/l967 Groos 72-272 GERALD A. DOST, Primary Examiner.

.'U.S. Cl. XR. 72-25 3

